Quick release hydraulic operator



' I Jhly'lZ, 1932. W, W D 1,867,393

QUICK RELEASE HYDRAULIC OPERATOR Filed NOV. 6, 1930 Faga. Fig.2. 6 45 Inventor: William JWoods,

His AfiEo'P-neg b WM Patented July 12 1932 UNITED STATES PATENT OFFICE WILLIAM J. WOODS, OF SCHENECTADY, NEW YORK, ASSIGNOR TO ELECTRIC COMPANY, A CORPORATION OF NEW YORK QUICK RELEASE HYDRAULIC OPERATOR Application filed November 6, 1930. Serial No. 493,903.

My invention relates to improvements in electro-hydraulic pressure operated devices such as described in the copending apphcation of lValter O. Lum, Serial No. 415,341, filed December 19, 1929, and assigned to the same assignee as the present invention..

The device described in the Lum application referred to comprises a vertical fluid cylinder in which is mounted a piston movable between an upper and a lower position, the piston being biased to its lower position.

v lYhen the piston has reached its upper or working position and the driving motor is deenergized to permit the piston to return to its initial position, the inertia of the rotating rotor ofthe motor and the impeller causes the impeller to continue to rotate for a short period of time and to continue to create a pressure on the underside of the piston, thus maintaining the piston in its upper position until the energy of rotation has been dissipated permitting the pressure to fall off and the piston to return to its initial position. This prevents immediate reset of the piston.

Hence, it is a principal object of my invention to provide an improved type of clectro-hydraulic operator in which the effect of inertia upon instant reset is eliminated as much as possible.

In the preferred embodiment of my invention I provide a fluid casing in which is mounted a piston movable between an upper and a lower position and biased to the lower position. An electric motor mounted on the top of the casing is connected by means of asplined shaft to an impeller pump housed within the piston proper. pump when driven by the electric motor ore";-

ates a pressure on the underside of the piston The impeller to lift the piston within the casing. The piston is of a smaller diameter than the casing and registering with the exhaust passages of the impeller pump are ports which under certain circumstances, as explained below, will permit the fluid which is forced from the top side of the piston to pass through the piston and back to the top side of the piston, thus rendering the pump ineffective to raise the pistonvwithin the cylinder. Concentric with thecylinder and filling the space between the cylinder proper and the side of the casing is a floating ring which is carried by the piston and which is biased by means of springs to a position below the ports in the sides of the pistons under certain conditions of pressure. When the piston is in its lower position this ring is forced against its bias by means of a shoulder in the interior of the casing to a position above the ports. In this position the oil which passes through the piston is forced to the underside of the piston and cannot reach the upper side of the piston until the floating ring is in the position below the ports.

When the electric motor is energized to drive the pump the pressure created by the pump maintains the ring in its upper position and lifts the piston within the casing.

Upon deenergization of the electric motor the pressure created by the pump begins to fall off and the spring biased ring in response thereto moves to its biased position, thus opening the ports to the upper side of the piston. In this way by bypassing the flu1d through the piston and permitting the fluid underneath the piston to pass up through the exhaust passages a quick reset of the piston is obtained since the inertia of the motor and pump is used to pump the oil through the piston back to the top side of the piston 1nstead of to the underside of the piston to create a pressure in the fluid to raise the piston. The biasing springs are adjusted so that at the slightest drop below the normal pressure created by the pump they will move to the lower or bypassing position.

A better understanding of my devlce Wlll be obtained by reference to the accompanying drawing in which Eig. 1 shows a cross section of my hydraulic operator in a positlon of rest withthe floating ring in its upper position; Fig. 2 shows a cross section of the piston taken at an angle. to that shown in Fig. 1 and showing the supporting means for the floating ring and the floating ring below the ports; and Fig. 3 shows the details of the construction of the piston proper.

Referring to the drawing, a fluid casing or cylinder 10 is provided with'the cover or cylinder head 11 and with the plugs 12 and 13 which permit the withdrawal of the fluid, such for example as oil, from the casing. Supported onthe top of the cover 11 is electric motor 14 which is provided with the dust cap 15 having a bearing for the rotor of the motor. Mounted for movement within the casing is the piston comprising the two parts 16 and 17. The two parts of the piston form the impeller pump housing for the impeller pump 18 which is driven from the electric motor 14 by means of the splined shaft 19. The shaft 19 for the pump is supported by means of the self-aligning bearing 20 which permits the shaft to vary from a vertical position when the piston moves up and down within the casing, thus eliminating any stresses or strains thatmight be due to any misalignment. A hearing 21 mounted in the cylinder head 11 supports the lower end of the motor shaft to which is connected the fan 22 for forcing a draft of cooling air through the motor proper. A floating ring 23surrounds the piston and can move in a parallel direction with respect to the piston to a position above or below the ports 15 and 15' in the lower part 16 of the piston.

Referring to Figs. 2 and 3, it will be seen that the parts 16 and 17 of the piston form a housing for the impeller 18 and provide the upper intake passages such as 24 and lower intake passages such as 25 and 26 and chamber 27 for leading oil to the top and'bottom parts of the impeller blades. The fluid is then expelled in a radial direction through the exhaust'passages, such as 28 and 29, to the under side of the piston, thus causing a pressure on the underside of the piston to raise the piston within the casing.

, on the underside of the piston falls below a In Fig. 2 will be seen the method by which the floating ring 23 is supported by the pis ;ton. Brackets 30 and 31 supported by the upper portion-17 of the piston and attached thereto by suitable screws in turn support the rods 32 and 33 on which the ring 23 slides.-

Springs 34 and 35 bias this ring to a position below the ports 15 and 15 when the pressure predetermined amount, for example, a pressure slightly less than that created when the lmpeller is rotated at its normal speed.

- Nuts 36 and 37 on the rods 32 and 33 permit ports the flui adjustment of the tension of the springs 34 and 35.

When the ring 23 is in a position above the exhausted by the pump the piston so that no pressure is created on the underside of the piston to raise the piston or to maintain the piston in raised position if the piston is in its raised position.

The piston has mounted thereon the bosses 39 and which are connected to the collar 38 by means of webs, the collar 38 being the supporting element for the self-adjusting bearing 20. Mounted in the bosses 39 and 40 are the rods 41 and 42 which support the bridge member 47 which in turn supports the work-engaging eye 48. These rods slide in the bearings and 46 on the cylinder head and the upward limit of movement of the piston is determined by the members 43 and 44 which contact with the bearings 45 and 46 when the piston is in its upper position.

The operation of the device is as follows: When the electric motor 14 is energized to rotate the impeller ump 18 fluid is led to the upper and lower sides of the impeller blades by means of the passages 24, 25, 26 and 27 as pointed out above and discharged through the exhaust passages 28 and 29 to the lower side of the piston. The pressure thus created by the pump causes the iston to be moved upwardly, the ring 23 eing maintained in its upper position due to the presmembers 43 and 44 the piston will remain in that position so long as the electric motor 14 is energized.

' When it is desired to return the piston to its initial position the motor 14 is deenergized. Then, as the energy of rotation of the rotating parts of the motor and rotor is slightly dissipated the pressure created thereby beneath the piston begins to fall slightly. Under ordinary circumstances there will be a slight delay in the return of the piston to its initial position depending upon the time necessary to dissipate the inertia of the rotating parts in the fluid until such time as the pressure created thereby is insufficient to support the piston within the cylinder. With the present invention, however, the springs 34 and 35 upon a slight decrease in pressure in the fluid will force the ring 23 to a position below the ports 15 and 15 in the piston. The fluid instead of being directed to the underside of the piston, as was the case while the impeller was rotating at its normal speed,

will now be bypassed from the top side of the piston, through the piston, through the ports 15 and 15' around the sides of the piston back to the upper side of the piston, and 011 on the underside of the piston will pass up through the exhaust passages 28 and 29, ports 15 and 15', to the upper side of the piston, thus causing the pressure beneath the piston to drop almost instantaneously to a zero value which will permit the piston to begin its return to initial position without any delay due to the inertia of the rotating parts of the driving motor and the impeller pump. 1

It will thus be seen that I have provided a unique method of overcoming the difliculties introduced in hydraulic operators by the inertia of the rotating parts and for providing a hydraulic operator in which the delay due to inertia is eliminated,.permitting the piston to begin its return to initial position almost instantaneously upon deenergizat1on of the driving motor.

The embodiment of the invention illustrated and described has been selected for the purpose of clearly setting forth the principles involved. It will be apparent, however, that the invention is susceptible of being modified to meet the different conditions encountered in its use, and I, therefore, aim to cover by the appended claims all of the modificat ons within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is

1 A hydraulic operator including a fluid caslng, a piston therein, a pump for creating a pressure within the fluid to move the piston, a driving motor therefor. said piston having means for bypassing fluid for rendering said pump ineffective to move said piston and means for rendering said last means effective when the pressure created by said pump falls to a predetermined value.

2 A hydraulic operator including a fluid casing, a piston therein movable between two positions and biased to one of said positions. a pump for creating a pressure within the fluid on one side of said piston to move the piston to the other position and maintain said piston therein, a driving motor therefor, said piston having means for lay-passing fluid under pressure through said piston to render said pump ineffective to maintain said piston in said other position, and means responsive to the pressure of said pump when said pressure falls to a predetermined value upon deenergizing said pump and cooperating with said piston for causing the by-passing action of said bypassing means.

3. A hydraulic operator including a fluid casing, a piston therein movable between two positions and biased to one of said positions, a pump for creating a pressure within the fluid on one side of said piston to move the I by said pump when said pressure falls to a predetermined value upon deenergizing said pump for rendering said by-passing means operative.

4. A hydraulic operator including a fluid casing, a piston therein movable between two positions and biased to one of said positions, a pump for creating a pressure within the fluid on one side of saidpiston to move the piston to the other position and maintain said piston therein, said piston having ports therein for by-passing fluid under pressure through said piston to render said pump ineffective to maintain said piston in said other position. and means responsive to a predetermined pressure upon deenergizing said pump for causing said by-passing action.

5. A hydraulic operator including a fluid casing, a piston therein, a pump for creating a pressure within the fluid to move said piston, a driving motor therefor, said piston having means for by-passing fluid for rendering the inertia of said pump and motor ineflective to actuate said piston when said motor is deenergized, and means responsive to a predetermined pressure of said pump upon deenergizing said motor for controlling said last means.

6. A hydraulic operator including a fluid casing, a piston therein movable between two positions and biased to one of said positions, a pump for creating a pressure within the fluid to move said piston to the other position, said pump while energized, maintaining said piston in said other position. said piston having means for bypassing fluid for rendering the inertia of said motor and pump ineffective to temporarily maintain said piston in said other position when said motor is deenergized,and other means responsive to the pressure created by said pump upon deenergization thereof for controlling said first means. v

7. A hydraulic operator including a fluid casing, a piston therein movable between two positions and biased to one of said positions, a pump for creatinga pressure within the fluid on one side of said piston to move said piston to the other position, said pump maintainingsaid piston in said other position while energized, ports in said piston forbypassing the fluid forced by said pump back v to'thc same side of said piston from which it was forced thereby rendering the inertia of said motor and pump in'eflective to temporarily maintain said piston in its other position whensaid motor is deenergized and a,

floating .ring cooperating with said piston and responsive to the pressure of said pump for controlling the by-passing action of said orts.. p 8. A hydraulic operator including a fluid casing, a piston therein movable between two positions and biased to one of said positions, a pump for creating afluid pressure to move said piston from its biased position to the other position, ports in said pistonfor bypassing fluid under pressure to the same side of said piston from which it was forced by said pump whereby said pump is rendered ineffective to move said piston, and a floating ring carried by said piston and responsive to the pressure of said pump for cooperating with said ports to control the by-passing action thereof.

9. A hydraulic operator including a fluid casing, a piston therein movable between two positions and biased to one of s id positions, a pump for creating a fluid pres ure to move said piston from its biased position to the other position and maintaining said piston in said position while said pump is energized,

' ports in said piston for by-passing fluid under pressure to the same side of said piston from which it was forced whereby said pump is rendered inefi'ective to maintain said piston in said other position, a floating ring carried by said piston and responsive to the pressure of said pump for cooperating with said ports to control the by-passing action thereof, and means biasing said ring to a position to permit said by-passing action to take place, said ring when said piston is in its biased position being positioned to prevent said by-passing action.

10. A hydraulic operator including a fluid cylinder, a piston therein, a pump for creating a fluid pressure to move said piston, ports in said piston for by-passing fluid through said piston to render said pump ineflective, a floating ring carried by said piston and biased to permit said ports to bypass fluid when the pressure of said pump is below a predetermined value but maintained in a position to prevent the by-passing action when the pressure created by the pump is above said predetermined value.

115 A hydraulic operator including a fluid casing, a piston therein movable between two positions and biased to one of said positions. a pump for creating a pressure on one side of said piston to move said piston from its biased position to the other position and maintaining said piston in said other position while said pump is energized, ports in said piston for by-passing fluid under pressure through said piston to render said pump ineffective to maintain said piston in said other position, a floating ring concentric of said piston and biased to take a position to one side of said ports when the pressure created by said pump is below a predetermined value to permit the by-passing action to take place,'but maintained in another position on i the other side of said ports when said pressure is above a predetermined value, to prevent said by-passing action, and means for maintaining said ring in said last position when said piston is in its biased position.

12. A quick reset hydraulic operator including a fluid casing, a piston therein movable between two positions and biased to one of said positions, a pump carried by said piston for creating a pressure in the fluid to move said piston from said biased position to the other position and maintaining said piston in said other position while said pump is energized. a driving motor for said pump, said piston forming a housing providing intake and exhaust passages for said pump, ports in said piston registering with said exhaust passages for by-passing fluid through said piston, and a member carried by said piston and cooperating with said ports to'connectsaid exhaust passages to the same side of the piston as said intake passage when said pumpv is deenergized to by-pass the fluid exhausted by said pump whereby said piston can return to its biased position without delay due to the inertia of said motor and pump as said motor and pump come to rest.

13. A quick reset hydraulic operator including a fluid casing, a piston therein movable between two positions and biased to one of said positions, a pump carried by said piston for creating a pressure in the fluid to move the piston to the other position and maintaining said piston in said other position while said pump is energized, a driving motor for said pump, said piston providing a housing with intake and exhaust passages for said pump, said piston having ports therein registering with said exhaust passages. a floating ring for connecting said ports to the intake side of said piston wherebv the fluid under pressure may be bv-passed from the intake side of the piston through said piston and back to the intake side of said piston, and means for biasing said ring to the bypassin position when the pressure developed by said pump falls to a predetermined value when said motor is deenergized, therebv permitting said piston toreturn immediately to its biased position.

14. A quick reset hydraulic operator in- I side of said piston when said motor is deenergized to by-pass the fluid under pressure whereby the effect of inertia of said motor and pump is rendered inefi'ective to maintain said pump in the other position.

In Witness whereof, I have hereto set my hand this fifth day of November, 1930.

WILLIAM J. WOODS. 

